function chklogin(obj)
{
	if(document.getElementById('username').value == ""){
		alert("用户名不能为空!");
		document.getElementById('username').focus();
		return false;
	}
	if(document.getElementById('upwd').value == ""){
		alert("密码不能为空!");
		document.getElementById('upwd').focus();		
		return false;
	}
	return true;
}